A portable computer device such as a hand-held calculator can store relatively large amounts of data. Transferring the data to/from the portable device either requires a high data rate or more time on a slower connection. A wired transfer is desirable for a large data transfer because wired connections typically have a higher data rate but it is not always practical to use a wired connection.
In the classroom environment, a wired connection would be preferable to download large data sets to the hand-held device, but wired connections are not always practical or convenient. A wireless connection is more practical but in many cases too slow for a larger data set. Further, some hand-held devices may not have a dedicated or permanent wireless connection.